JP2009218661A - Imaging device with image distortion correcting function - Google Patents

Abstract

An imaging apparatus having an image distortion correction function capable of correcting a perspective effect in accordance with a shooting scene even in a small and thin imaging optical system.
An image pickup apparatus according to the present invention includes an image pickup optical system that condenses an optical signal from a subject, an image pickup element that converts the optical signal into an image signal, and a plurality of distance information to the subject. The distance information acquisition units 103, 104, and 106 that output the image, the posture information detection unit 105 that outputs the posture information of the device itself, and the image that corrects the perspective effect of the image signal using the distance information and the posture information. And a processing unit 107.
[Selection] Figure 1

Description

  The present invention belongs to the technical field of image distortion correction, and relates to an imaging apparatus having an image distortion correction function capable of correcting a perspective enhancement of an image due to a perspective effect and obtaining a good image.

  In recent years, image pickup apparatuses such as digital still cameras have been remarkably developed, and models with small size and light weight and a high pixel count are rapidly spreading. The imaging optical system of a digital still camera is also corresponding to this, and a small and thin lens is required and developed. In particular, there is an increasing demand for a digital still camera that can be easily carried and can be photographed with one imaging optical system from the wide-angle side to the telephoto side.

  As the imaging optical system becomes smaller and thinner in this way, it will be difficult to maintain sufficient basic optical performance such as various aberration characteristics and resolution characteristics, especially distortion that occurs on the wide-angle side. Has been a major problem in maintaining optical performance. Therefore, a correction technique for removing distortion by compressing and expanding a photographed image has been developed and put into practical use. For this reason, it has become possible to obtain a captured image with little distortion on the wide-angle side even if a relatively small and thin imaging optical system is used.

  On the other hand, in addition to the aberration characteristics of the imaging optical system, perspective enhancement of a subject in photographing a structure is known, that is, a perspective effect, particularly on the wide angle side. When the correction of distortion aberration proceeds on the wide angle side by the distortion aberration correction technique by compressing / decompressing the captured image, the perspective effect that has occurred on the wide angle side becomes a relative problem. In particular, on the wide-angle side, the perspective effect may be promoted in order to correct the barrel aberration of the imaging optical system.

  Until now, a comparatively large imaging optical system has very little distortion on the wide-angle side, and thus the problem of perspective emphasis due to the perspective effect has been revealed. Therefore, for subjects that are likely to have a sense of incongruity due to the perspective effect, such as shooting in high-rise buildings, the effect of the perspective effect can be mitigated and natural captured images can be obtained by using a special lens such as a tilt lens. It is possible.

  When shooting a high-rise building using a small and thin imaging optical system, the perspective effect is emphasized due to the lack of perspective effect correction, resulting in a captured image that differs from visual observation. Causes a sense of incongruity.

In order to solve this problem, Patent Document 1 in the technical field of an external recognition device for a vehicle discloses two angles that are assumed to be parallel to each other because the depression angle due to the steady pitch angle variation of the vehicle such as increase or decrease in the number of passengers A technique is disclosed in which a travel path dividing line is detected and corrected by determining its parallelism.
Japanese Patent Laid-Open No. 10-40499

  However, in a camera used in a vehicle external environment recognition device, two traveling road dividing lines on a road are detected and image processing is performed, so that the traveling road dividing lines and the like that are known to be parallel in advance are known. It is difficult to apply to a general subject where an object does not always exist.

  On the other hand, a camera that performs shooting using a tilt lens has a problem that adjustment is difficult because a dedicated tilt lens is required and the amount of the tilt must be set visually.

  The present invention has been made to solve the above problems, and an object of the present invention is to correct a perspective effect according to a shooting scene even in a small and thin imaging optical system without using a dedicated tilt lens. An object of the present invention is to provide an imaging apparatus having an image distortion correction function capable of performing the above-described processing.

  In order to solve the above conventional problems, an imaging apparatus according to the present invention includes an imaging optical system that collects an optical signal from a subject, an imaging element that converts the optical signal into an image signal, and A distance information acquisition unit that outputs a plurality of distance information, a posture information detection unit that outputs posture information of the device itself, and an image processing unit that corrects a perspective effect of the image signal using the distance information and the posture information And having. Since the perspective effect of the image signal is corrected using the posture information of the device itself and the distance information to the subject, the perspective effect is corrected according to the shooting scene even in an imaging device having a small and thin imaging optical system. There is an effect that can be.

  In the imaging apparatus according to the aspect of the invention, the imaging optical system includes a focus lens for focusing the optical signal on the imaging element, and the distance information acquisition unit transmits the optical signal to the imaging element. The distance information to the subject corresponding to the position information of the focus lens at the time of focusing may be output. The present invention can be easily applied to an imaging apparatus having a contrast type autofocus function.

  In the imaging apparatus of the present invention, the imaging optical system includes a focus lens for focusing the optical signal on the imaging element, and a moving lens capable of moving in a plane perpendicular to the optical axis of the imaging optical system. The distance information acquisition unit may output distance information to the subject corresponding to a moving amount of the moving lens when the optical signal is focused on the image sensor. The present invention can be easily applied to an imaging apparatus having a lens shift type camera shake correction function.

  In the imaging apparatus of the present invention, the imaging optical system has a focus lens for focusing the optical signal on the imaging element, and the imaging element is a plane perpendicular to the optical axis of the imaging optical system. The distance information acquisition unit outputs distance information to the subject corresponding to the amount of movement of the image sensor when the optical signal is focused on the image sensor. Good. The present invention can be easily applied to an imaging apparatus having a CCD shift type camera shake correction function.

  In the imaging apparatus of the present invention, the image processing unit corrects the perspective effect of the image signal when the subject is substantially vertical, and does not correct the perspective effect of the image signal when the subject is not substantially vertical. This may be a feature. For a subject that is inappropriate to correct the perspective effect, by correcting the perspective effect, there is an effect that a good image can always be obtained regardless of the subject.

  The image pickup apparatus of the present invention may be characterized in that the posture information is an elevation angle or a depression angle of the own apparatus. Even when looking up at the subject or looking down at the subject, there is an effect that a good image can always be obtained.

  The imaging apparatus according to the present invention may be characterized in that a plurality of pieces of distance information to the subject correspond to a plurality of regions aligned in a vertical direction of the image signal.

  As described above, according to the present invention, when performing image distortion correction that alleviates perspective emphasis due to the perspective effect, the correction information is calculated using the posture information of the own device and the distance information to the subject, thereby reducing the size and thickness. In this imaging optical system, it is possible to provide an imaging apparatus having an image distortion correction function capable of correcting a perspective effect according to a shooting scene.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
(1. Configuration)
FIG. 1 is a block diagram showing a configuration of a digital still camera according to the first embodiment of the present invention.

  As shown in FIG. 1, the digital still camera 100 of the present invention includes an imaging optical system 101, an imaging element 102, an imaging optical system control unit 103, a focus position determination processing unit 104, an attitude information detection unit 105, and a distance information storage unit. 106, an image processing unit 107, and a memory storage unit 108. The imaging optical system 101 includes a zoom lens 101a, a focus lens 101b, and a camera shake correction lens 101c. The image processing unit 107 includes a preprocessing unit 107a, a correction information calculation unit 107b, a distortion correction processing unit 107c, and an image conversion processing unit 107d.

  The imaging optical system 101 includes a plurality of lenses (groups), and focuses an optical signal of a subject on the imaging element 102. The zoom lens 101a changes the focal length of the optical system 101 by moving in the direction of the optical axis O-O ′. The focus lens 101b moves in the direction of the optical axis O-O ′ to focus the optical signal of the subject on the image sensor 102. The camera shake correction lens 101c corrects the camera shake of the photographer by moving in a plane perpendicular to the optical axis O-O '. The image sensor 102 is an element that converts an optical signal of a subject collected by the image pickup optical system 101 into an image signal, and a CCD image sensor, a CMOS image sensor, or the like can be used.

  The imaging optical system control unit 103 moves the zoom lens 101a in the direction of the optical axis OO ′ to change the focal length of the optical system 101, and moves the focus lens 101b in the direction of the optical axis OO ′ to optic the subject. The image signal is focused on the image sensor 102, and the shutter unit and iris unit (both not shown) provided in the image pickup optical system 101 are controlled in accordance with the condition of the subject to appropriately expose the image sensor 102. Give the amount. The imaging optical system control unit 103 simultaneously sends the focal length of the imaging optical system 101 and the position information of the focus lens 101b to the in-focus position determination processing unit 104.

  The focus position determination processing unit 104 determines whether the optical signal of the subject is focused on the image sensor 102 from the image signal converted by the image sensor 102. Whether or not the optical signal of the subject is focused on the image sensor 102 is determined by sending a control signal to the imaging optical system control unit 103 and moving the focus lens 101b in the optical axis OO ′ direction by a minute distance. This is performed depending on whether or not the contrast of the image signal converted by the image sensor 102 is maximized.

  FIG. 2 is a diagram of the image sensor 102 as viewed from the optical axis O-O ′ direction. Whether or not the optical signal of the subject is focused on the image sensor 102 is determined for the three areas A, B, and C on the image sensor 102 shown in FIG. That is, a control signal is sent to the imaging optical system control unit 103, and each of the areas A, B, and C is converted by the imaging element 102 while moving the focus lens 101b by a minute distance in the optical axis OO ′ direction. The position information of the focus lens 101b that maximizes the contrast of the image signal is acquired.

  The in-focus position determination processing unit 104 maximizes the contrast of the focal length of the imaging optical system 101 and the image signal converted by the imaging element 102 for each of the regions A, B, and C from the distance information storage unit 106. Distance information to the subject corresponding to the position information of the focus lens 101b is acquired. The distance information storage unit 106 stores distance information to the subject corresponding to the focal length of the imaging optical system 101 and the position information of the focus lens 101b. The in-focus position determination processing unit 104 sends the image signal converted by the image sensor 102 to the pre-processing unit 107a, and distance information to the subject for each of the areas A, B, and C acquired from the distance information storage unit 106. Is sent to the correction information calculation unit 107b.

  The pre-processing unit 107a performs pre-processing such as white balance correction, gamma correction, and scratch correction on the image signal sent from the in-focus position determination processing unit 104, and the pre-processed image signal is converted into a distortion correction processing unit. Send to 107c.

  The posture information detection unit 105 detects posture information (elevation angle) of the digital still camera 100 of the present invention and sends it to the correction information calculation unit 107b. An acceleration sensor or the like can be used for the posture information detection unit 105. In recent years, digital still cameras are often equipped with an acceleration sensor or the like to correct camera shake of a photographer. The acceleration sensor detects the acceleration of gravity when the digital still camera 100 of the present invention is stationary. Since the acceleration of gravity changes when an elevation angle is given to the digital still camera 100 of the present invention, posture information (elevation angle) can be obtained. Further, the posture information detection unit 105 may be configured to use the own weight information of the camera shake correction lens 101c. Control is performed so that the center of the camera shake correction lens 101c is positioned on the optical axis O-O 'except when correcting camera shake of the user. The self-weight information of the camera shake correction lens 101c can be obtained from the driving force at this time. When the elevation angle is given to the digital still camera 100 of the present invention, the weight information of the camera shake correction lens 101c changes, so that posture information (elevation angle) can be obtained. Moreover, the structure which incorporates a mechanical inclinometer may be sufficient.

  The correction information calculation unit 107b is a digital still camera 100 of the present invention sent from the posture information detection unit 105 and the distance information to the subject for each of the areas A, B, and C sent from the in-focus position determination processing unit 104. From the posture information (elevation angle), correction information necessary for correcting the perspective effect is calculated for the image signal preprocessed by the preprocessing unit 107a, and is sent to the distortion correction processing unit 107c.

  The distortion correction processing unit 107c corrects the perspective effect on the image signal sent from the preprocessing unit 107a using the correction information sent from the correction information calculation unit 107b, and converts the corrected image signal into an image. The data is sent to the processing unit 107d.

  The image conversion processing unit 107d performs image signal compression such as JPEG on the image signal sent from the distortion correction processing unit 107c, or stores the image signal in the memory storage unit 108 without performing image signal compression (so-called RAW image signal). . As the memory storage unit 108, a semiconductor storage device using a nonvolatile memory such as an SD card (registered trademark) or a compact flash (registered trademark), a hard disk, or the like can be used.

Details of operations of the correction information calculation unit 107b and the distortion correction processing unit 107c will be described later. The imaging optical system control unit 103, the in-focus position determination processing unit 104, and the distance information storage unit 106 constitute a distance information acquisition unit of the present invention.
(2. Operation)
Next, the operation of the digital still camera 100 according to the first embodiment of the present invention will be described. 3, 4, and 5 are diagrams illustrating the operation of the digital still camera 100 according to the first embodiment of the present invention. When taking a picture of a high-rise building from the ground as shown in FIG. 3, if you look up at the high-rise building so that the angle of view reaches the top of the high-rise building, the visual appearance is as shown in FIG. On the other hand, in the captured image, perspective emphasis occurs due to the perspective effect as it goes to the periphery, and the captured image as shown in FIG. 4B is stored in the memory storage unit 108.

  In the digital still camera 100 of the present invention, as shown in FIG. 5, the focus position determination processing unit 104 uses the focal length of the imaging optical system 101 and the position information of the focus lens 101b sent from the imaging optical system control unit 103. Based on the distance information storage unit 106, distance information l, m, and n to the subject for each of the regions A, B, and C is acquired from the distance information storage unit 106 and sent to the correction information calculation unit 107b. Further, the posture information detection unit 105 detects posture information (elevation angle θ) of the digital still camera 100 of the present invention and sends it to the correction information calculation unit 107b.

  The correction information calculation unit 107b is a distance information l / m / n to the subject for each of the regions A, B, and C sent from the in-focus position determination processing unit 104 and the present invention sent from the posture information detection unit 105. From the posture information (elevation angle θ) of the digital still camera 100, it is determined whether or not the subject is a vertical structure such as a high-rise building.

  FIG. 6 shows an example of a method for determining whether a subject is a vertically built structure such as a high-rise building. FIG. 6A is a diagram showing a case where the subject is a vertically built structure such as a high-rise building, and FIG. 6B is a diagram showing a case where the subject is a mountain slope or the like. The angle α is an angle formed by the center of the region A and the center of the region B, and the center of the region B and the center of the region C, and is a known angle corresponding to the focal length of the imaging optical system 101. The distance information l · m · n to the subject for each of the regions A, B, and C and the posture information (elevation angle θ) of the digital still camera 100 of the present invention are also known.

  Accordingly, in FIG. 6A in the case where the subject is a vertically built structure such as a high-rise building, when the horizontal distance from the digital still camera 100 of the present invention to the high-rise building that is the subject is X, the equation ( The relationship 1) is established.

X = lcos (θ + α) = mcos θ = ncos (θ−α) Equation (1)
At this time, the relationship of Expression (2) is also established.

l>m> n Formula (2)
On the other hand, in FIG. 6B when the subject is a mountain slope or the like, the relationship of Equation (2) is satisfied, but the relationship of Equation (1) is not satisfied. In the case of FIG.6 (b), Formula (1) becomes Formula (1) '.

l cos (θ + α)> m cos θ> n cos (θ−α)> X Formula (1) ′
Therefore, when both the expressions (1) and (2) are established, it can be determined that the subject is a vertically built structure such as a high-rise building.

  When the correction information calculation unit 107b determines that the subject is a vertically built structure such as a high-rise building, the distance information l · m · n to the subject for each of the regions A, B, and C and the present invention From the posture information (elevation angle θ) of the digital still camera 100, correction information necessary for correcting the perspective effect is calculated for the image signal preprocessed by the preprocessing unit 107a, and the distortion correction processing unit Send to 107c.

  Here, the calculation of the correction information will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of calculation of correction information. The correction information calculation unit 107b calculates an enlargement / reduction ratio at each position of the image signal preprocessed by the preprocessing unit 107a.

  A case will be described in which a photographed image having a height H is corrected to an image having a height L in a plane perpendicular to the optical axis O-O ′ of the digital still camera 100 of the present invention. From the posture information (elevation angle θ) and the half angle of view β of the digital still camera 100 of the present invention at the time of shooting, the relationship of Expression (3) is established between the height H and the corrected height L.

L = H cos θ−H sin θ tan β Formula (3)
Here, tan β is obtained as shown in Expression (4) from the diagonal dimension of the image sensor 102 of the digital still camera 100 of the present invention and the focal length of the imaging optical system 101 at the time of shooting.

tan β = (diagonal dimension of the image sensor) ÷ (focal length at the time of shooting) Expression (4)
Therefore, the corrected height L can be obtained from the equations (3) and (4).

  However, when the height L after correction is obtained in this way, the perspective effect is completely corrected, and an image with a sense of incongruity may be obtained. For example, when the focal length of the digital still camera 100 of the present invention at the time of shooting is 28 mm in terms of 35 mm, and the posture information (elevation angle θ) is about 29 °, the corrected height L is the height H. It becomes about 1/2. Therefore, by applying a certain coefficient (for example, about 0.8) to the posture information (elevation angle θ), it is possible to obtain an image with a moderately corrected perspective. This coefficient may be different depending on the focal length and posture information (elevation angle θ) of the digital still camera 100 of the present invention at the time of shooting.

  The plane perpendicular to the optical axis OO ′ of the digital still camera 100 of the present invention is based on the closest one of the distance information l, m, and n to the subject for each of the areas A, B, and C. By doing so, it is possible to prevent the corrected image from being cut off.

  The calculation of the correction information related to the vertical direction of the image has been described above, but the same applies to the calculation of the correction information related to the horizontal direction of the image. However, in the calculation of the correction information related to the left-right direction of the image, it is desirable that the calculation is performed symmetrically with respect to the center in the left-right direction of the image. As a result, the corrected image can be prevented from being cut off also in the left-right direction of the image.

  By repeating the above calculation, correction information at each position in the vertical and horizontal directions of the image is calculated and sent to the distortion correction processing unit 107c.

  The distortion correction processing unit 107c corrects the perspective effect on the image signal sent from the preprocessing unit 107a using the correction information sent from the correction information calculation unit 107b, and converts the corrected image signal into an image. The data is sent to the processing unit 107d. FIG. 8 is a diagram illustrating correction of the perspective effect. FIG. 8A is a diagram showing an image signal sent from the pre-processing unit 107a. FIG. 8B is a diagram in which the distortion correction processing unit 107c performs expansion correction according to the screen position, and the perspective effect is alleviated. It is a figure which shows an image signal. Specifically, the pixel on the left side from the center in FIG. 8A is electronically moved in the diagonally upward left direction, and the pixel on the right side from the center is electronically moved in the diagonally upward right direction. This causes a shortage of pixels, but electronic interpolation is performed using information on neighboring pixels. Note that the broken lines in FIGS. 8A and 8B are described to indicate the degree of perspective emphasis, and are not included in the actual image signal.

  Next, a case where the correction information calculation unit 107b cannot determine that the subject is a vertically built structure such as a high-rise building will be described. FIG. 9 is a diagram illustrating a case where the subject cannot be determined to be a vertically built structure such as a high-rise building. FIG. 9 shows a case where shooting is performed while looking up at a forehead with a depression on a wall. In this case, since the relationship between the expressions (1) and (2) is not established, it cannot be determined that the subject is a vertically built structure such as a high-rise building. In the case of FIG. 9, Expression (1) becomes Expression (1) ", and Expression (2) becomes Expression (2) '.

lcos (θ + α) <mcosθ <ncos (θ−α) <X Formula (1) ″
l≈n> m Formula (2) ′
Therefore, the correction information calculation unit 107b does not send the correction information to the distortion correction processing unit 107c, and the distortion correction processing unit 107c does not correct the perspective effect for the image signal sent from the preprocessing unit 107a.

  FIG. 10 is a diagram illustrating another case where the subject cannot be determined to be a vertically built structure such as a high-rise building. FIG. 10 shows a case where a person stands in front of a vertically built structure such as a high-rise building. In this case, since the relationship between the expressions (1) and (2) is not established, it cannot be determined that the subject is a vertically built structure such as a high-rise building. In the case of FIG. 10, Expression (1) becomes Expression (1) "", and Expression (2) becomes Expression (2) ".

X = l cos (θ + α) >> m cos θ≈n cos (θ−α) Equation (1) ′ ″
l >> m≈n Formula (2) ''
Therefore, the correction information calculation unit 107b does not send the correction information to the distortion correction processing unit 107c, and the distortion correction processing unit 107c does not correct the perspective effect for the image signal sent from the preprocessing unit 107a.

  In the first embodiment of the present invention, the perspective effect is corrected in the vertical direction. However, the perspective effect can be corrected in the same way in the horizontal direction. In that case, it is necessary to provide an area for acquiring distance information to the subject in the left-right direction.

  In the first embodiment of the present invention, three areas A, B, and C are used for acquiring distance information to the subject. However, the distance information only needs to be acquired from a plurality of areas. It is not limited to three. The acquisition of the distance information to the subject is performed by acquiring the position information of the focus lens 101b that maximizes the contrast of the image signal converted by the image sensor 102 for each of the regions A, B, and C. However, the present invention is not limited to this. Information on the distance to the subject may be acquired by a phase difference detection method or an active method.

Further, in the first embodiment of the present invention, it is assumed that the shooting is performed while looking up at the high-rise building from the ground, but conversely, even when shooting is performed while looking down from the roof of the high-rise building, Perspective effects can be corrected in the same way.
(Embodiment 2)
(1. Configuration)
In the first embodiment of the present invention, the distance information to the subject is acquired for each of the plurality of regions. In the second embodiment of the present invention, the digital still camera captures images to correct the camera shake of the photographer. When the camera shake correction lens 101c is provided in the optical system 101, the camera shake correction lens 101c is moved before photographing to acquire distance information to the subject in a single area. Since the configuration of the digital still camera according to the second embodiment of the present invention is the same as the configuration of the digital still camera according to the first embodiment of the present invention, description thereof is omitted. The camera shake correction lens 101c is an example of the moving lens of the present invention.
(2. Operation)
FIG. 11 is a diagram illustrating an effect obtained by moving the camera shake correction lens 101c. 11A shows a state where the camera shake correction lens 101c is not moved, FIG. 11B shows a state where the camera shake correction lens 101c is moved upward, and FIG. 11C shows a state where the camera shake correction lens 101c faces downward. Each moved state is shown.

  In FIG. 11A, since the image stabilization lens 101c is not moved, the center of the image stabilization lens 101c is on the optical axis OO ′, and the image signal converted by the image sensor 102 is the optical axis OO. The range of the angle of view corresponding to the focal length determined by the position of the zoom lens 101a is captured centering on '.

  The in-focus position determination processing unit 104 receives the position information of the focus lens 101b from the distance information storage unit 106 that maximizes the contrast of the focal length of the imaging optical system 101 and the image signal converted by the imaging element 102 for the region B. The distance information m to the subject corresponding to is acquired.

  In FIG. 11B, since the camera shake correction lens 101c is moved upward, the center of the camera shake correction lens 101c is above the optical axis OO ′, and the image signal converted by the image sensor 102 is the optical axis O. A range of an angle of view corresponding to a focal length determined by the position of the zoom lens 101a is captured downward by an angle α with respect to −O ′.

  The in-focus position determination processing unit 104 receives the position information of the focus lens 101b from the distance information storage unit 106 that maximizes the contrast of the focal length of the imaging optical system 101 and the image signal converted by the imaging element 102 for the region B. The distance information n to the subject corresponding to is acquired.

  In FIG. 11C, since the camera shake correction lens 101c is moved downward by the same movement amount as that in FIG. 10B, the center of the camera shake correction lens 101c is below the optical axis OO ′. The image signal converted by (1) captures the range of the angle of view corresponding to the focal length determined by the position of the zoom lens 101a upward by an angle α with respect to the optical axis OO ′.

  The in-focus position determination processing unit 104 receives the position information of the focus lens 101b from the distance information storage unit 106 that maximizes the contrast of the focal length of the imaging optical system 101 and the image signal converted by the imaging element 102 for the region B. The distance information l to the subject corresponding to is acquired.

  During the above operation, the position of the zoom lens 101a is fixed. In this way, the distance information l · m · n to the subject can be acquired in the single region B.

  FIG. 12 is a diagram illustrating the operation of the digital still camera 100 according to the second embodiment of the present invention. First, the center of the camera shake correction lens 101c is fixed on the optical axis O-O '(state shown in FIG. 11A), and distance information m to the subject is acquired for the region B. Next, the camera shake correction lens 101c is moved upward (upper body in FIG. 11B), and distance information n to the subject for the region B is acquired. Finally, the camera shake correction lens 101c is moved downward (state shown in FIG. 11C), and the distance information l to the subject for the region B is acquired.

  From the distance information l · m · n to the subject and the posture information (elevation angle θ) of the digital still camera of the present invention, the perspective effect can be corrected as in the first embodiment of the present invention.

  If the upward and downward movement amounts of the camera shake correction lens 101c are set to the same fixed value, the angle α is also a fixed value. The upward and downward movement amounts of the camera shake correction lens 101c may be different values. When the posture information (elevation angle θ) of the digital still camera of the present invention is relatively small, the downward movement amount of the camera shake correction lens 101c may be larger than the upward movement amount. At this time, two fixed values of the angle α with respect to the upward movement amount of the camera shake correction lens 101c and the angle β with respect to the downward movement amount are necessary.

  In addition, angle information corresponding to the movement amount of the camera shake correction lens 101c is stored in the distance information storage unit 106 in advance, and the camera shake correction before shooting sent from the imaging optical system control unit 103 by the in-focus position determination processing unit 104 is stored. Angle information corresponding to the amount of movement of the lens 101c may be acquired from the distance information storage unit 106 and sent to the correction information calculation unit 107b.

  When a vertically built structure such as a high-rise building exists relatively downward within the range of the angle of view corresponding to the focal length determined by the position of the zoom lens 101a, the camera shake correction lens 101c is moved downward. In this case, the distance information 1 to the subject in FIG. 12 may become infinite. This is because, since the angle (θ + α) in FIG. 12 is large, not the distance to the top of a vertically built structure such as a high-rise building but the sky above it is measured. In such a case, the downward movement amount of the camera shake correction lens 101c may be reduced until a finite value is measured.

  At this time, if angle information corresponding to the movement amount of the camera shake correction lens 101c is stored in the distance information storage unit 106, angle information corresponding to an arbitrary movement amount of the camera shake correction lens 101c can be acquired.

  Further, the relationship between the amount of movement of the camera shake correction lens 101c and the angle information can be obtained by optical simulation using design data of the imaging optical system 101. At this time, the angle information is stored in the distance information storage unit 106 as a function of the movement amount of the camera shake correction lens 101c using the center of gravity position of the imaging according to the spectral sensitivity ratio of the image sensor 102, so that the data amount is relatively small. It is desirable because it has less versatility.

  In the second embodiment of the present invention, the camera shake correction lens 101c is moved. However, the same effect can be obtained by moving the image sensor 102 instead of the camera shake correction lens 101c. For image stabilization, a lens shift system that moves the camera shake correction lens and a CCD shift system that moves the image sensor (CCD) have been put into practical use. However, either system can acquire multiple distance information to the subject. Can be used.

As described above, in the second embodiment of the present invention, when the distance information of the subject is acquired, the camera shake correction function of the digital still camera 100 is used to obtain a plurality of distance information l · m to the subject in the single region B. Since n can be acquired, it is possible to reduce errors due to variations in region positions.
(Other embodiments)
In the first embodiment and the second embodiment of the present invention, the operation system of the digital still camera of the present invention is not limited. The image distortion correction function of the present invention may be configured to be automatically performed regardless of the settings of the digital still camera of the present invention, or may be performed by a photographer performing a predetermined setting. It may be configured. Further, it may be configured such that the photographer can adjust the intensity of correction by performing a predetermined setting. Further, when the photographer makes a predetermined setting, the image distortion correction is intentionally performed even if the elevation angle or depression angle of the digital still camera of the present invention is 0 ° or a minute angle. May be. Thus, the image distortion correction function of the present invention is not limited by the operation system of the digital still camera of the present invention.

  The image pickup apparatus having the image distortion correction function of the present invention can correct the perspective emphasis of the image by the perspective effect without being aware at the time of shooting, so that the image pickup apparatus such as a digital still camera, a digital video camera, and a camera-equipped mobile phone can be used. Useful to apply.

The block diagram which shows the structure of the digital still camera which is an Example of this invention. The figure which looked at the image sensor from optical axis O-O 'direction The figure which shows operation | movement of the digital still camera which is 1st Example of this invention (photographing condition) The figure (photographed image) which shows operation | movement of the digital still camera which is 1st Example of this invention. The figure (distance information) which shows operation | movement of the digital still camera which is 1st Example of this invention. The figure which shows an example of the judgment method whether a to-be-photographed object is a structure built vertically, such as a high-rise building The figure which shows an example of the calculation of correction information Diagram showing correction of perspective effect Figure (1) showing a case where it cannot be determined that the subject is a vertically built structure such as a high-rise building Fig. 2 shows a case where the subject cannot be determined to be a vertically built structure such as a high-rise building. The figure which shows the effect by moving the image stabilization lens The figure which shows the operation | movement of the digital still camera which is the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Digital still camera 101 Imaging optical system 101a Zoom lens 101b Focus lens 101c Camera shake correction lens 102 Imaging element 103 Imaging optical system control part 104 Focus position determination processing part 105 Attitude information detection part 106 Distance information storage part 107 Image processing part 107a Front Processing unit 107b Correction information calculation unit 107c Distortion correction processing unit 107d Image conversion processing unit 108 Memory storage unit

Claims (7)

An imaging optical system that collects optical signals from the subject;
An image sensor for converting the optical signal into an image signal;
A distance information acquisition unit that outputs a plurality of distance information to the subject;
A posture information detector that outputs posture information of the device itself;
An image processing unit that corrects a perspective effect of the image signal using the distance information and the posture information;
Having
An imaging apparatus characterized by that. The imaging optical system is
A focus lens for focusing the optical signal on the image sensor;
Have
The distance information acquisition unit
Outputting distance information to the subject corresponding to position information of the focus lens when the optical signal is focused on the image sensor;
The imaging measure according to claim 1, wherein: The imaging optical system is
A focus lens for focusing the optical signal on the image sensor;
A moving lens that can move in a plane perpendicular to the optical axis of the imaging optical system;
The distance information acquisition unit
Outputting distance information to the subject corresponding to a moving amount of the moving lens when the optical signal is focused on the image sensor;
The imaging apparatus according to claim 1. The imaging optical system is
A focus lens for focusing the optical signal on the image sensor;
Have
The image sensor is
Can move in a plane perpendicular to the optical axis of the imaging optical system,
The distance information acquisition unit
Outputting distance information to the subject corresponding to the amount of movement of the image sensor when the optical signal is focused on the image sensor;
The imaging apparatus according to claim 1. The image processing unit
When the subject is substantially vertical, correct the perspective effect of the image signal,
When the subject is not substantially vertical, the perspective effect of the image signal is not corrected.
The imaging apparatus according to any one of claims 1 to 4, wherein the imaging apparatus is characterized. The posture information is
The elevation or depression of your device,
The imaging apparatus according to any one of claims 1 to 5, wherein The plurality of distance information to the subject is
Corresponding to a plurality of regions aligned in the vertical direction of the image signal;
The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus.

Images